Apparatus for forming castings



Aug. 27, 1935. CRMGO 2,012,679

APPARATUS FOR FORMING CASTINGS Filed Jan. 12, 1954 Patented Aug. 27,1935 UNITED STATES FATE [OFFICE f {APPARATUS Foe FORMING CASTINGS JohnM. Craigo, Hartford, Conn.

"Application a y 12, 1934, Serial No. 70 .352

' v 7 Claims. (01. 22-9) I nating from the molds ordies irregularitiesdue to airbubbles and uneven distribution of the investment material.

In the accompanying drawing, .I have illustrated a suitable mechanicalstructure by means of which my improved method may be executed.

It is to be understood, however, that ,the;drawingis for the purpose ofillustration only'a'nd is not to be considered as limiting the inventionthe scope of which is to be measured entirely by the'scope of theappended claims.

In the accompanying drawing,

Fig. 1 is an elevational view of a suitable. mechanical apparatus forcarrying out the idea of the invention; I I a 'Fig. 2 is an elevationalview on an enlarged scale of a portion of the apparatus. illustrated inFig. 1; V

i Fig. 3 is a sectional view on theline' 3'3-.of Fig. 2;

Fig. 4 is a sectional viewon .the line 14-4" or Fig. 3; and I x Fig. 5is a fragmentary'elevationaluview of a portion of my improved apparatus,particularly illustrating certain features of the method of operationthereof.

Referring to the drawing in detail, the numeral,

l generally indicates a machine used in form-' ing castings, such as areused for dental crowns and inlays. This machine comprises a flat baseportion II from oneside of which a standard l2 extends verticallyupwardly. Thisstandard I2 is provided at its upper end with a horizontalportion i3 overlying the upper surface of the base H and through thishorizontalfportion adjacent to the extremity'thereof there is a'vertical bore l4 through which extends a vertically adjustable member ortool holder I 5. Vertical movement of the member IS in the bore l4 maybe obtained by suitable means, such as the pinion I 6 jour .naled in theportion l3 of the standard l2 and provided with gear teeth l1. whichcooperate with the teeth Ila. of a gear rack formed on the side of themember l adjacent to "the pinion. The

shaft of the pinion l6 maybe extended outside of the standard and may beprovided int'thisextended portion witha lever I8 extendingtherethroughfor rotating the pinion. The vertically adjustable member I 5 may belockedin any position offvertical adjustment by a suitable means,

such as a set screw 20. The memberor tool holder I5 is provided at thelower end thereof with an axial wel1'22 forthe reception of ,tool stems,and suchtool stems may be locked in the tool holder by suitable means;such as a set screw 24 carriedby the tool holder in: the portion thereofthrough which the well 22, extends. A vertical bore or aperture 25 isprovidedinthe'base l l immediately b'elowthe tool holderl5 in axialalinement with the bore M; the purpose of the bore '25 being to'support,variouspieces of operative mechanism, such as anvils, dies, turrets,and mold .casingsupon thebasea,

In carrying outmy improved method, I utilize. a pattern .holder 21preferably formed-of. brass or other suitable heatresisting material- 3This pattern holder, as illustrated in Fig. 2, comprises t a circulardisk portion 28 upon one side of. which is formedradepending portion 29having a somewhat conical or-spherical contour. holder is furtherprovided with a concentric aper- .20 The molded ture ,30 extendingtherethrough. The patterns,

as indicated at 32, and 33, are formed of wax or moldine, or othersuitable 'material, and are. at-' tached to metallic pins, asindioatedat 35. The ends of these pins oppositethe'ends to which thepatterns areattached are inserted in the aper ture30, and the apertureis then .fille d .with a material such as a. suitable wax composition tohold the patterns in fixedpositionrelative to the pattern holder.

The investment ormoldmaterial iscontained in a suitable receptacle,suchas the mold ring 31, thebottom ,of which is closed bya'rubber dam38. This receptacleis mounted in a turret,

I generallyindicated at .40, having an upper flanged disklike portion 4|v.up'onwhich isformed a con centric stem "42 adaptedto. fit in theaperture 25 for rotation: therein. This construction locates thereceptacle 3'! immediately below the tool holder. l5Hin axial ,alinementtherewith 'for con centric rotation relative thereto. Forum purpose ofsecuring the pattern holder 21 to .the'tool holder l5, I-have provided amechanism, general ly indicated at: 45, comprising averticalstande ard41.ofzpreferably.oblongacross sectionlhaving at the upper end thereof a48 of thinner. section. r

To the portion 48, I have secureda stem 50 by suitable means, such asriveting orwelding. This stem 50'fitsintothe well 22in theltool holderhorizontal extension I5 and maybe locked thereinby, the set screw 24. a

When the members are suitably assembled the verticalportion of thestandard is, offset from the common axis of the tool holder and theaperture 25 on the side of the axisi'adjacent to'the standard 12; J Thelower endoflthe vertical'portion 4'! of the support 45is provided with ahori.-.

zontal aperture 53 extending therethrouglnand ill in this aperture isjournaled the stem of a bracket member, generally indicated at 55 inFig. 3. This bracket member 55 comprises a cylindrical journal portion56 terminated at one end by an abutment flange 58.. The journal portion55 may be secured in the aperture5'3 by suitable'means, such as thebearing screw 60. A stem portion 62 extends from the flange 58 on theside thereof ope, 1 positethe journal portion 56 and terminates in aflat disklikemember 65 the sides of which are cut away along chordsperpendicular to thekaxis of the journal and stem to proyidea retainingmember in the form of a zon'e 'o'f a circle; "This retaining member isprovided along the opposite circumferential sides thereof with dependingflanges, as indicated ato l lnEF-ig-sl '4 and order to secure thepattern holder 21 to the pore tion 6 5 of the bracket 55, I-haveprovided a pair of. 'clips 68 and 69 inthe form-of flat strap'or barmembers :having their outer extremit iesbent under, as indicated at T2to iorm dogsor abutments to underlie the disk portion: 2801 the patternholder-21 and-latch the same to the bracket. The extrenn-ties of themembers {58an'd 68 are bent upwardly, as indi'cated at fi; to dormfinger pieces for moving the members. Y overlappingportion ofthesemembers are out away, as

. 19 is inserted between the fingerpi-eces -15 to nor 3o indicated atIi-in 3,- and'acornpressionspring mally urgethe finger pi eces apart/andat the same time urge the dogs 12 into position to en'gage the diskportion 28 of the member 21. These mem =bers t8 and '69 are secured tothe portion-65' 0f the member 55 by meansof rivets or screws, asindicated at 89, extending through-elongatedslots 82 having theirheadspositionedabove and bearing on the upper suriac'es of the members."in -combination with the slidable members 68 and $9,

I have provided a centering device in the zform of i a block 84 securedto the disk 65 by screws;-as indisengage both of the dogs .12 beneaththe flangedsportion 28 of the lpattemihotder 21;

journal portion of 0f the member 55115 provided within the aperture '53with a plurality foi -radial depressions 36 particularly illustratedv mFig. 4. These depressions. are 'spacedl' at 'somewl'iat, tin- ,eoualangles around the circumference- M the journal" member. 'and' are.adapted to be engaged bya detent 92 pivoted in the 'vertical'portion l'l of the bracket means of a transverse pin93. The-detent 'SZ- hasahandle port-ionSl extending outof the vertical member 41 and at dogoft-latch portion .95 adapted to engage :in the recessesnu, one side "ofthe 'dog 95 being roundedmofi" softhat the member 55 may berotated-about its; axis in one direction, but will be releasablyrestrained fromrotation in-the opposite direction by the engagement-ofthedetent in-one of thejrecesses. :A depression Sit-is pr'ovidedlin thevertical member 41 for the. accommodationof the detent filaand thisrecess is preferably covered-.jby a plate 8-! secured tothe member 41 bysuitable means,:such

as screws "98 .1 Above the detent the vertical member-is provided with'a bore in which is inserted one, end-50f :a compression spring 99 thelower 1 end of, which bears againstthetop of the detent 92 to cause thedetentto automatically engage in the recesses 90. It will be observedthat the detent may be disengaged from any one of the recesses by adownward pressure upon the handle portion 94 thereof. 1 v iQReferringnow to Fig.2, it will be observed that the disk portion 28 of thepattern holder 21 is 'lmurled, as indicated at I00.

The improved method of operation of this device is substantially asfollows: After the wax patterns fland 33 are secured to the patternholder 21 by means of the pin 35, the finger pieces 75 are pressedtogether and the flange 28 of the pattern holder is inserted betweentheflanges 6'! of the bracket 55. The finger pieces are then released,whereupon the pattern holder is rotatably secured in the bracket; Thereceptacle 3! is filled with investment material and-mounted upon *theturret 40 beneath' the pattern holder; 'i-t being und'ers'tood that myimproved bracket has already been-properly mounted in the machined?! andthat thetool holder i5 is in its uppermost position, as illustrated inFig. '1. i The tool holder is'then lowered-by rotation of the pinion"1-6 to immerse the patterns 32 and 3-3 in the investment materialcontained in the receptacle'fi. After the patterns are completelyimmersed, the pinion I5 is rotated :in theopposite direction to raisethe tool holder l5 to its uppermost position; The pattern holder 2 is'then rotated or oscillated inithe bracket 55, and the bracket is turnedtovarious angular positions about a 'verticai-circumference, asindicated in Fig. 5, duringT-tnis rotation. The e'fl'ect' of thisrotation is to cause the investment material to spread evenlybverthe iwax surfaces of the patterns end-if one df th'e patterns happens to beacrown in the form of a hollow cup, as illustrated at 33, r,otation of-the pattern holder in an inverted position 'willcause the:investmentmaterial to flow down into the interior of this cup and-fill the-same.The

knurled edge provided on the disk portion 28provides :a means forrotating the pattern holder and also a means for vibrating the sameduring rotatron by reason of the engagement of the-knurled edge with theends of the flanges 61. This vibrationhas the efiect of a shakeractiona-nd tends to eliminate air bubbles from the investmentmateriaLcoastedupon the pattern and to distribute the investment material evenlyover 'theyentire surface of each pattern. Mter the investment materialhas been suitably distributed by this :.rotation and vibration atdifferent angles aroundtha axis 'of the bracket member '55, thebracketniem'ber is rotated to bring the pattern holder into uprightposition, as illustrated in Figs. El. and 2, the tool holder 15 isthenlowered-b'y rotation :of the pinion 1'5 until the patterns 32ended-are again imm'ersed in the investment material contained in thereceptacle 3'1. sired,;1at'this point, the pattern holder may bereleased from the bracket by releasing the detents 12 therefrom "in themanner described above, and the-casting ring31, together with the plate*holder 2l ,.mayrbe removed 'from the maohine I II and setaside for theinvestment material to harden andithe machine used for another mold.After the-investment material .has'prope erly set and hardened, heat isapplied thereto to melt the wax patterns and 33, and releasethe samefrom the pattern holder 21 The pattern holdenis then removed from themold; and the I melted waxpoured out 6f the mold. tnfteriathisoperation, melted metal: may be poured into the mold to ior'm thecastings :flor which the patterns It 'de- 32 and 33 are made. Theconical or spherical shape of the portion 29 of the pattern holderprovides in the top of the mold a funnel to direct the molten metal intothe channels provided'by the pins 35 leading to the molds provided bythe patterns 32 and 33.

It will be observed that by this improved method and apparatus I haveprovided a means whereby a plurality of castings may be rapidly madewith the same machine, and also one wherein the castings will besmoothly and accurately formed, since there will be no air bubbles inthe mold and no lateral movement of the patterns upon their immersion inthe investment material.

While I have illustrated and described a particular mechanicalembodiment of the idea of the invention, it is to'be understood that theinvention is not to be limited thereby, but the scope thereof is to bemeasured entirely by the scope of the appended claims.

Having now described my invention so that others skilled in the art mayclearly understand v the same, whatI desire tosecure by Letters Patentis as follows:

1. A device for preparing a mold for making castings frompatternscomprising, a receptacle for investment material, a patternholder, means for-supporting the receptacle and pattern holder invertical alinement, means for immersing said patterns in said investmentmaterial and withdrawing them therefrom, and means for securing saidpattern holder to said supporting means for rotation or oscillation ofsaid holder about axes disposed at right angles to each other when saidpatterns are withdrawn from said investment material, to cause saidinvestment material to spread evenly over the surfaces of said patterns.

2. A device for preparing a mold for making castings from patternscomprising a receptacle for investment material, a pattern holder, meansfor supporting the receptacle and pattern holder in vertical alinement,means for immersing said patterns in said investment material andwithdrawing them therefrom, means for securing said pattern holder tosaid supporting means for rotation of said holder about axes disposed atright angles to each other when said patterns are withdrawn from saidinvestment material and means 'for vibrating said patterns when saidholder. is

rotated about one of said axes to cause said investment material tospread evenly over the surfaces of said patterns.

3. A device for preparing a mold for making castings from patternscomprising a receptacle for investment material, a pattern hold-er,means for supporting'the receptacle and pattern holder in verticalalinement comprising, a base, a standard, and a vertically movablebracket rotatably secured to said standard, means for detachablysecuring said pattern holder to said bracket for rotation relativethereto about axes located at right angles to the axis of rotation ofsaid bracket, means for raising and lowering said bracket to immersesaid patterns in said investment material and withdrawthem therefromwhereby said pattern holder may be rotated when saidpat terns arewithdrawn from said investment material to cause the investment materialadhering to said patterns to spread evenly over the surfaces thereof,and means for locking said bracket at various angular positions aboutits axis of rotation.

4. A device for preparing a mold for making castings from patternscomprising a receptacle for investment material, a pattern holder, meanscomprising a base, a standard, and a bracket rotatable about ahorizontal axis for supporting said 1 receptacle and pattern holder invertical alinement, means for detachably securing said pattern holder tosaid bracket for rotation relative thereto, means for moving saidbracket to immerse said patterns in said investment material andwithdraw them therefrom, whereby said patterns may be rotated whenwithdrawn from said investment material to cause said investmentmaterial to spread evenly over the surfaces of said patterns, and meansfor positioning said bracket at various angles around said horizontalaxis whereby said pattern holder may be rotated in. various planesparallel to said horizontal axis 5. A device for preparing a mold formaking castings from patterns comprising a receptacle for investmentmaterial, a pattern holder, means comprising a base, a standard, and abracket for supporting said'receptacle and pattern support in verticalalinement, means for detachably seduring said pattern holder to saidbracket for rotation relative thereto, means for moving said bracket toimmerse said patterns in said investment material and withdraw themtherefrom whereby said patterns may be rotated when with- ,drawn fromsaid investment material to cause said investment'material to spreadevenly over the surfaces of said patterns, and a knurled rim on saidpattern holder to cause vibration of said said ho-lderrelative to from,latch means for detachably securing .said

pattern holder to saidbracket for rotationrela tive thereto about anaxis at right'angles to said horizontal axis, means for positioning saidbracket at various angular positionsabout said horizontal axis, andaknurled rim on said pattern holder whereby the same may be manuallyrotated while held at various angular positions by said bracket. 7. Adevice for preparing a mold for making a base and a standard, a toolholder mounted in said standard for vertical movement towards and awayfrom said base, means for moving said tool holder, a receptacle forinvestment material located onsaid base below said tool holder, abracket carried by the lower endof said tool holder and supported forrotary movement about a horizontal axis, said bracket having a .plateportion provided with curved depending flanges at its opposite sides, apattern holder having a knurled rim positioned slidably mounted on saidplate portion and having their outer extremities bent under said flangesto form abutments adapted to underlie said rim -of the pattern holderand latch the same to the bracket, a spring between said clips andnormally urging the same into holding position, and means for securingsaid bracket in various positions of angular adjustment with respect tosaid tool holder.

JOHN M. CRAIGO.

1 castings from patterns comprising a frame having between and engagingsaid flanges, a pair of clips

